I have this radio, and it works, but in the lower volume range the sound is dull, higher frequencies are missing. It is very difficult to understand a speaker. At high volume sound is ok. This is caused by a capacitor C130, and I want to remove it. The problem is that I can find no way to open the thing. Of course I removed the 5 screws on the back, but I cannot find any reason why the back panel is still strongly held in place. I prefer not to use brute force. Is there anyone who can help??